Rose oxide, or 2-[2-methyl-prop-1-en-1-yl]-4-methyl-tetrahydropyrane, of formula ##STR1## is a compound of special renown in the fragrance industry. Since its discovery in 1960 [see Swiss Pat. No. 395,406], numerous scientific publications have related to new syntheses for its preparation. A synthetic approach, starting from 3-methyl-but-2-en-1-al and 2-methyl-but-1-en-4-ol, was suggested by J. P. H. Tyman and B. J. Willis [cf. Tetrahedron Letters, 51, 4507 (1970)] and by Firmenich [see G.B. Pat. No. 2,036,004].
The present invention relates to a new process for the preparation of rose oxide, which process makes use of cheap commercially available starting materials and enables the preparation of the desired product in good yields.